INTRODUCTION
Studies examining cognitive functioning in people with substance use disorders indicate
deficits in memory, executive functions and information processing speed have been
observed, and may be related to cognitive differences predating substance use as well as the
effects of long-term heavy use.1–3 Gould1 reports that the brain regions and neural processes
that underlie addiction overlap extensively with those that support cognitive functions, and
with continued drug use, cognitive deficits ensue that exacerbate the difficulty of
establishing sustained abstinence. Regarding methamphetamine (MA) use specifically,
research suggests cognitive impairments in memory, learning, psychomotor speed, and
information processing are common in chronic MA users, and these impairments have the
potential to compromise the ability of MA users to engage in, and benefit from
psychosocially based substance abuse treatment.4 A study by Simon et al5 indicates that MA
use has been associated with impairment on recall tasks, sequencing, mental flexibility,
psychomotor speed, manipulation of information, selective attention and the ability to ignore
irrelevant information. In addition, findings from neuroanatomical, neurochemical, and
imaging studies support the conclusion that MA abuse causes damage to multiple transmitter
systems that are distributed throughout the brain.6